The invention is generally concerned with the very large scale integration of electronic elements or of circuits integrated in a housing, or of electronic modules, which are designated as “smart card module” in the present invention.
In many areas of electronics, sensor technology and microsystems engineering, the production requirements exert pressure that drives increasing miniaturization and increasing productivity by combining subsystems in more highly integrated structures. The trend toward ever more highly integrated and more compact designs that can also be used directly in smart cards already leads to the use of components that are arranged directly in modules. Such modules are, for example, the contactless modules of the known design series MCC, MOB or MOA. In these modules, the chip is contact-connected by means of so-called wire bonds and enveloped by a plastic enclosure (mold). Owing to the dictates of construction, this type of integration leads to a large total thickness of the module and thereby makes integration into a smart card more difficult.
Furthermore, contactless smart card modules are known, such as the MFCC1 module, for example. In the MFCC1, the chip is contact-connected by means of NiAu contacts using so-called flip-chip mounting. In flip-chip mounting, the chip is mounted with the active contact-connecting side facing downward directly toward the substrate or circuit carrier. As a result, a covering of the chip is no longer necessary. Consequently, the total thickness of the smart card module is principally determined by the chip thickness. However, such a contactless smart card module is highly susceptible to mechanical loading and has low flexural stiffness on account of the small chip thickness.
A method designated as frame adhesive bonding is likewise known. The desired stabilization or stiffening of the module is intended to be ensured by means of this method. In frame adhesive bonding, a frame is adhesively bonded onto the leadframe before further processing. However, this requires an adhesive that directly influences the total thickness of the module. Typical frame heights are 300 μm, and so module constructions of the required thickness cannot be realized. Furthermore, there is the risk here of delamination between frame and leadframe.